﻿/*
* Copyright (c) 2010-2012 Tesla Engine Group
* 
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/

using System;
using Tesla.Math;

namespace Tesla.Bounding {
    /// <summary>
    /// Intersection record for Ray-Primitive tests. May contain any number of
    /// intersections. The array passed to the record will be sorted based on 
    /// each intersection's distance to the ray.
    /// </summary>
    public struct PrimitiveIntersectionRecord {
        private IntersectionRecord[] _records;
        private static readonly IntersectionComparer _comparer = new IntersectionComparer();

        /// <summary>
        /// Gets the intersection by its index.
        /// </summary>
        /// <param name="index">Zero-based index of intersection</param>
        /// <returns>The intersection record, or null if does not exist</returns>
        public IntersectionRecord? this[int index] {
            get {
                if(_records == null) {
                    return null;
                }
                return _records[index];
            }
        }

        /// <summary>
        /// Gets the number of intersections contained in this record.
        /// </summary>
        public int IntersectionCount {
            get {
                if(_records == null) {
                    return 0;
                }
                return _records.Length;
            }
        }

        /// <summary>
        /// Gets the closest intersection, if it exists.
        /// </summary>
        public IntersectionRecord? ClosestIntersection {
            get {
                if(_records != null && _records.Length > 0) {
                    return _records[0];
                }
                return null;
            }
        }

        /// <summary>
        /// Gets the farthest intersection, if it exists.
        /// </summary>
        public IntersectionRecord? FarthestIntersection {
            get {
                if(_records != null && _records.Length > 0) {
                    return _records[_records.Length - 1];
                }
                return null;
            }
        }

        /// <summary>
        /// Creates a new PrimitiveIntersectionRecord. This will sort the intersections by
        /// their distances to the ray's origin.
        /// </summary>
        /// <param name="intersections">Array of intersection records</param>
        public PrimitiveIntersectionRecord(IntersectionRecord[] intersections) {
            _records = null;
            if(intersections != null) {
                _records = intersections;
                Array.Sort<IntersectionRecord>(_records, _comparer);
            }
        }
    }
}
